Thursday, September 8, 2016

Renaissance Magazine Newsletter #3

Being rich in the Middle Ages led to an unhealthy life

In the Middle Ages only wealthy town
people could afford to eat and drink from beautiful, colored glazed cups and
plates. But the glazing was made of lead, which found its way into the body if
you ate acidic foods. This has been revealed by chemical investigations of
skeletons from cemeteries in Denmark and Germany.

Being wealthy in the Middle Ages was
not all benefits: Wealthy people were more exposed to the toxic heavy metal
lead than the poor.

"Lead poisoning can be the
consequence when ingesting lead, which is a heavy metal. In the Middle Ages you
could almost not avoid ingesting lead, if you were wealthy or living in an
urban environment. But what is perhaps more severe, is the fact that exposure
to lead leads to lower intelligence of children", says Associate Professor
Kaare Lund Rasmussen, Department of Physics and Chemistry, University of
Southern Denmark (SDU).

Together with colleagues Rasmussen
has published a series of chemical and anthropological analyzes of 207
skeletons from six cemeteries in northern Germany and Denmark. The paper is
published in the Journal of Archaeological Science: Reports.

Practical, beautiful -- and poisonous

"There really is a big
difference in how much lead, the individuals from the cemeteries had in their
bodies. This depended on whether they lived in the country or in a town. We see
almost no lead in the bones from rural individuals, while the levels of this
toxic metal were high in urban individuals", says Rasmussen.

In the Middle Ages wealthy Danes and
Germans mainly lived in towns, while the rural population was generally poorer
and more isolated. The wealthy could afford to eat and drink of glazed pottery,
and this was the main source of lead poisoning.

"In those days lead oxide was
used to glaze pottery. It was practical to clean the plates and looked
beautiful, so it was understandably in high demand. But when they kept salty
and acidic foods in glazed pots, the surface of the glaze would dissolve and
the lead would leak into the food", says Rasmussen.

In the country, glazed pottery was
seemingly used more rarely. And even if you had the money, it would have been
more difficult to get by. Instead, the country people used unglazed pottery and
thus unknowingly saved themselves from exposure to the toxic lead.

Glazed pottery was not the only
source of lead in the towns. Lead was also present in coins, stained glass
windows and lead tiles on the roofs of important buildings. Drinkingwater was
often collected from the roof, and this may also have been an important source
of lead.

Rasmussen studied skeletons from six
cemeteries.

The cemeteries in Rathaus Markt in
Schleswig (Germany) and Ole Worms Gade in Horsens (Denmark) are both situated
on the coast and people buried here were from medieval towns that were more
wealthy and more in contact with the outside world than most rural population.

The rural population was represented
by cemeteries in St. Clements outside of Schleswig (Germany), Tirup outside of
Horsens (Denmark), Nybøl in Jutland (Denmark) and St. Alberts Chapel on the
island of Ærø (Denmark).

"The exposure was higher and
more dangerous in the urban communities, but lead was not completely unknown in
the country. We saw that 30 pct. of the rural individuals had been in contact
with lead -- although much less than the townspeople."

There were different levels of
exposure in the towns. 19 pct. (10 individuals) from the cemetery in Rathaus
Markt had lead levels above normal. In Horsens all 25 individuals had levels
above normal.

Mercury was given as medicine

The research team also tested the
skeletons for their content of mercury. Mercury was used to prepare the color
cinnabar, for gilding and as medicine against leprosy and syphilis.

The results of the measurements show
that the urban population was more exposed to mercury than the rural
population. Mercury was administered to treat especially leprosy, which almost
half of the individuals in the study suffered from.

However the study reveals a
difference in how effective the treatment was in the towns.

"Maybe they had more expertise in mercury treatments
in Schleswig than in Horsens", says Rasmussen.